class_docstr: Compute quantile regression lines
  
  {usage}
  
  Parameters
  ----------
  {common_parameters}
  quantiles : tuple, default=(0.25, 0.5, 0.75)
      Quantiles of y to compute
  formula : str, default="y ~ x"
      Formula relating y variables to x variables
  method_args : dict, default=None
      Extra arguments passed on to the model fitting method,
      :meth:`statsmodels.regression.quantile_regression.QuantReg.fit`.
  
  See Also
  --------
  statsmodels.regression.quantile_regression.QuantReg
  plotnine.geoms.geom_quantile
code: def setup_params(self, data):
      params = self.params.copy()
      if params["formula"] is None:
          params["formula"] = "y ~ x"
          warn("Formula not specified, using '{}'", PlotnineWarning)
      try:
          iter(params["quantiles"])
      except TypeError:
          params["quantiles"] = (params["quantiles"],)
  
      return params
  
file_path: plotnine/plotnine/stats/stat_quantile.py
imports: from warnings import warn
  import pandas
  from ..doctools import document
  from ..exceptions import PlotnineWarning
  from .stat import stat
label_desc: Use image node_id 1 for calling the stat_quantile obj's underlying member method code with example usage: obj.setup_params(data) and returns: params